Corrugated magnetic cover for electric utilities

ABSTRACT

This invention comprises a removable reusable cover for an electric panel, said cover composed of light weight 3-ply corrugated material which adheres to said electric panel by means of electrically nonconducting magnetic strips on rear edges of said cover to prevent exposure of the interior of said electric panel, with a front side of the cover providing a surface to contain printed warnings and the like.

CROSS-REFERENCE TO PRIOR APPLICATION

This is a continuation of prior patent application Ser. No. 08/582,165filed Jan. 2, 1996, which is incorporated herein by reference, nowabandoned.

FIELD OF THE INVENTION

This invention relates to temporary electric utility covers in generaland, more particularly, to covers having magnetic supporting meansthereon for use as temporary covers of electrical fuse and circuitbreaker panels and the like.

BACKGROUND AND SUMMARY OF THE INVENTION

During the construction or repair of an electrical panel or junction boxand the like it is necessary for the electrician to remove the cover ordoor to the unit for extended periods of time. A temporary cover is veryuseful and necessary for safety when the unit needs to be leftunattended. Often an electrician will leave panels exposed or may resortto applying a piece of cardboard or similar material with tape to servethis purpose. Usually, this type of temporary, makeshift cover does notconvey the potential safety hazard and may not adhere adequately to theunit for extended periods of time. This approach would not meet federalsafety standards.

Temporary protective covers for switches and outlets have been disclosed(U.S. Pat. Nos. Des. 307,538; Des. 345,142; 4,907,711; and 5,003,128).These covers do not use magnetic adhering means nor are they practicallyadaptable for large electrical panels. On the other hand, signs withmagnetic adhering means have been disclosed (U.S. Pat. Nos. 2,957,261and 3,372,503). These magnetic signs require a large number of smallmagnets or magnetic strips that occur at no greater intervals than 3inches throughout the area of the sign. A large number of small magnetsoffer the disadvantages of high cost and complexity of manufacturingcompared to magnetic strips. On the other hand, the use of numerousmagnetic strips places said strips within the central area of the sign.In the case of the electrical covers, magnetic strips in the centralarea of the cover would not be useful because there would be no surfacefor adherence. In addition, placing electrically conducting magneticstrips in proximity to electrical parts is unwanted and unsafe. Thus,with electrical panel covers the magnets must be confined to the edgesof the cover, still provide sufficient force for adherence, and, forsafety, must not be electrically conducting.

The difficulties in creating a cover with magnetic adhering means for anelectrical panel are that the cover has to be strong and durable and themagnets, being functionally restricted to the edges of the cover, haveto provide sufficient magnetic force to prevent the sign from slippingor from being readily dislodged. Thus, the relationship between theweight of the cover and the adhering force of the magnets must be suchthat the cover will be held firmly in place. Furthermore, for safetyreasons, the magnetic adhering means must be electrically nonconducting.Since critical features of the cover are that it have some rigidity inthree dimensions and resist penetration with reasonable use, it isessential that the cover be constructed of sufficiently strong durablematerials. The mass and density of standard materials disclosed in theprior art for these signs require an extensive amount of magnets.Construction of electric panel covers similar to that described forsigns would make the covers expensive, heavy, and inconvenient totransport or store. Also, present industrial safety standards requiretemporary electrical panel covers to be composed of at least two layers,unlike signs disclosed in the prior art which are only one layer.

OBJECTS OF THE INVENTION

It is a particular objective of the present invention to so design amagnetic cover for electric panels that is semi-rigid, durable,corrugated (3-ply), and lightweight wherein said cover is electricallynonconducting, protects personnel from exposure to electrical parts, andwill remain in place with ordinary use and contact.

A further objective is to provide a temporary removable electrical panelcover to keep unauthorized people from exposed energized panel parts, tobe used while working on an electrical panel when there is a need toleave the panel unattended.

It is another object of the present invention to provide a temporaryelectrical panel cover that is easy to store, transport, apply, andremove and which may be used any number of times.

SUMMARY OF THE INVENTION

With the above and further objectives and advantages in view, and withthe provision of an efficient magnetic cover of simple and inexpensiveconstruction, the invention comprises novel construction and adaptationand combination of parts hereinafter described and claimed. A preferredembodiment of this invention is a cover constructed of very lightweightcorrugated 3-ply plastic with thin strips of magnetic material on twoopposite edges on the rear side of the cover, thus enabling the sign tobe held by force of magnetism to a foundation surface composed ofmaterial which is attracted to the magnetic strips. The cover isrectangular in shape with the magnetic strips being applied adjacent tothe longer edges of the rectangular cover. The length and width of thecover are made preferably slightly larger than the standard length andwidth of an electrical panel box.

BRIEF DESCRIPTION OF THE DRAWINGS

The details and advantages of this invention will become more apparentin the specifications, descriptions, and drawings, of which:

FIG. 1 is a perspective rear view of the temporary magnetic electricalcover.

FIG. 2 is an end view of the magnetic cover mounted in place over anelectrical panel box.

FIG. 3 is a front view of the magnetic cover.

FIG. 4 is a side view of the magnetic cover in place over an electricalpanel box.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a perspective view of a preferred embodiment of theelectric panel cover 1. The cover is rectangular in shape with thelonger sides 4 ranging between 1.5 feet and 6.0 feet in length,preferably 4 feet, and the shorter sides 3 ranging between 1 foot and 3feet, preferably 1 foot 29/16 inches or 1 foot 81/4 inches. Thepreferred dimensions accommodate standard electric panels. Elongatemagnetic strips 5 are bonded on the rear side 2 of the cover and aredisposed and extend adjacent, or along, the edges of the longer sides 4.The nonelectrically conducting magnetic strips can be obtained frommanufacturers of magnetic materials and are bonded to the rear edges ofthe cover with pressure sensitive adhesive on one side of the magneticstrip. The magnetic strips range in width from 0.75 inches to 1.5inches, preferably 1.25 inches and range in thickness from 0.030 inchesto 0.093 inches, preferably 0.06 inches. The cover 1 is composed of3-ply corrugated electrically nonconducting material such as plastic orcardboard which ranges in thickness from 0.079 inches to 0.220 inches,preferably 0.196 inches. The thickness of each ply, 2, 6, and 7, rangesfrom 0.01 inches to 0.02 inches, preferably 0.018 inches. The number ofcorrugations 6 range from 4 per inch to 6 per inch, preferably 5 perinch. This type of 3-ply plastic can be obtained from manufacturers ofplastic materials.

FIG. 2 shows an end view of the cover illustrating the front 7 and therear 2 aspects of the cover with the magnetic strips 5 projecting fromthe rear side of the cover along the longer sides 4 of the cover.

Panel boxes on which the cover 1 would be used are well known in theindustry and have been used for many years. Such a known panel box isshown at 8 in FIG. 4. A front portion of such a standard electricalpanel box 8 also is shown in FIG. 2 having side edges, or edge portions,8a, 8b with substantially aligned planar front surfaces facing outwardlytoward panel cover 1. As is well-known these opposed side edges of theelectrical panel box are spaced apart to define a face opening 10 of aselected width. Such panel boxes have substantially similar top andbottom edges aligned in the plane of edges 8a, 8b to define asubstantially rectangular face opening 10 for the panel box permittingaccess to the interior of the electrical panel box. Such a known panelbox is described herein to define the environment in which the presentinvention is used.

The panel cover 1 has a width along shorter sides 3 which is greaterthan the width of the opening 10 between electrical box edge portions8a, 8b, such that the panel is adapted to completely span and cover theopening 10 in the front of the electrical box. Further as is seen inFIG. 4 the panel is longer, or taller, than the electrical box for thesame purpose.

As is illustrated in FIG. 2 the magnetic strips 5 are spaced apart adistance slightly greater than the opening width between edges 8a, 8b,such that they may engage edge portions 8a, 8b which are of a materialwhich is attracted to a magnet. The magnetic strips will be held throughmagnetic attraction against side edges 8a, 8b.

As is illustrated in FIGS. 1, 2, and 4 the panel cover 1, andparticularly its rear side 2, is substantially planar. The magneticstrips 5 also are substantially planar and extend substantiallycontinuously adjacent the opposed longer sides 4. Each magnetic striphas a first end disposed closely adjacent one of the end edges 3 andextends along its respective side edge to terminate at the opposite endof the strip closely adjacent the opposite end edge 3. Since themagnetic strips extend substantially continuously along the length, orheight, of the panel cover 1 a user may easily place the cover on anelectrical panel box without undue effort to align the same verticallywith selected portions of the panel box. Explaining further, it is asimple matter for a user to grasp the panel cover, hold it in thegenerally upright orientation illustrated in FIGS. 1 and 4, and place itover the opening in the electrical panel box with magnetic strips 5engaging and magnetically attaching the panel cover to opposed edges 8a,8b of the panel box.

FIG. 3 shows a frontal view of the cover and how the front portion 7 ofthe cover can be used as a sign to provide warning information.

FIG. 4 shows a side view, along a longer side 4, of the cover in placeon an electrical panel box 8 with its supporting elements 9. The edgesof the electrical panel box 8 and adjacent supporting elements 9 form afoundation surface composed of material which is attracted to themagnetic strips and upon which the cover adheres to prevent exposure ofthe interior of the electric panel box 8. The front 7, the rear 2 andthe corrugations 6 of the cover show the 3-ply composition of the coverand their relationship to the magnetic strips 5 which cause the cover toadhere to the electric panel box 8 and supporting elements 9.

There has been shown and described in detail a preferred embodiment ofthis invention. However, it should be apparent to one skilled in the artthat this invention may incorporate other embodiments in many differentforms. The present disclosure serves as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the embodiment illustrated. The scope of the invention is describedin the appended claims.

I claim:
 1. A removable reusable cover for an electric panel having aface opening defined in part by opposed edges which are composed ofmaterial which is attracted to a magnet and are spaced apart to define aselected opening width, the cover comprising a substantially planar3-ply corrugated sheet composed of electrically nonconducting materialhaving opposed side edges spaced apart a distance greater than saidselected opening width, said sheet having a front side and rear side andbeing composed of a nonconducting plastic material ranging in overallthickness from 0.079 to 0.220 inches with the thickness of each ply inthe panel ranging from 0.01 to 0.02 inches and the number ofcorrugations ranging from 4 to 6 per inch, and electricallynonconducting elongate magnetic strips on the rear side of said sheetadjacent the edges of said sheet positioned to engage the edges of theelectric panel, wherein said cover may be held in place by said magneticstrips engaging the edges of such electric panel and extend across saidopening in the panel to prevent exposure of the interior of the electricpanel, with said front side of the sheet providing a surface to containprinted warnings and the like.
 2. The cover of claim 1, wherein thepanel is substantially rectangular and has opposed end edges extendingbetween said side edges, and each of said magnetic strips issubstantially continuous having a first end disposed closely adjacentone of said end edges and extending along its respective side edge toterminate at the opposite end of the strip closely adjacent the oppositeend of the panel.
 3. The cover of claim 1, wherein a magnetic strip hasa width in a range of from 0.75 to 1.5 inches and a thickness in a rangeof from 0.030 to 0.093 inches, lies substantially flat against the rearside of the panel, and is adhered thereto.
 4. A removable reusable coverfor an electric panel having a face opening defined in part by opposededges which are composed of material which is attracted to a magnet andare spaced apart to define a selected opening width, the covercomprising a substantially planar 3-ply corrugated sheet composed of anonconductive plastic material ranging in overall thickness from 0.079to 0.220 inches with the thickness of each ply in the panel ranging 0.01to 0.02 inches and the number of corrugations ranging from 4 to 6 perinch, the cover being substantially rectangular having opposed sideedges spaced apart a distance greater than said selected opening widthand opposed end edges extending between the side edges, said sheethaving a front side and a rear side, and electrically nonconductingmagnetic strips on the rear side of said sheet adjacent the side edgesof the sheet positioned to engage the edges of the electric panel, eachof said magnetic strips being substantially continuous having a firstend disposed closely adjacent one of said end edges and extending alongits respective side edge to terminate at the opposite end of the stripclosely adjacent the opposite end of the panel, a magnetic strip havinga width in a range of from 0.75 to 1.5 inches and a thickness in a rangeof from 0.030 to 0.093 inches, aligned substantially flat against therear side of the panel and adhered thereto, wherein said cover may beheld in place by said magnetic strips engaging the edges of suchelectric panel and extending across said opening in the panel to preventexposure of the interior of the electrical panel, with said front sideof the sheet providing a surface to contain printed warnings and thelike.